where \(f\)  is the Coriolis parameter. This upper branch balance, which
is the leading order balance of the steady state zonal mean zonal
momentum equation, is expected to hold within the equivalent cells
on Jupiter (see SI). This balance can hold down to a depth of only
a few bars, as inferred from energy considerations [1]},
implying flows from belts to zones within the cloud layer of the Jovian
atmosphere. In the lower branch of the terrestrial Ferrel cells, the
balance is between the Coriolis force and a surface drag [2]}.
 Since the Jovian atmosphere lacks a bottom solid boundary, surface
drag cannot act to oppose the Coriolis force, although it has been
suggested that if the cells extend as deep as the jets [3]},
the Lorentz force can act as a magnetic drag [4]}, [1]}, [6]}. Another possible mechanism that allows the jets to be barotropic in the upper atmosphere and decay in the interior is the presence of a stable layer, as was shown lately in several studies [7]}, [8]}, [9]}.
<FIGURE>